It is apparent also that the diffraction spots in the SAED patterns are less broad in Fig. 5
near the bottom surface of the billet than in Fig. 4 in the vicinity of the center of the billet so that the boundaries introduced by ECAP have lower angles of misorientation near the bottom surface. This observation is consistent with the predictions of finite element analyses showing less deformation in the vicinity of the lower surface in ECAP [24–26].